The purpose of this project is to study the effects of various chemicals on drug and xenobiotic metabolism in various types of cells in the lung. Of particular interest are those compounds which are metabolized by the cytochrome P-450 monooxygenases. The rat was chosen as the experimental animal because it, like man, is subject to induction of these metabolizing systems by certain drugs and chemicals. Factors which alter the metabolic activity of the lung may play an important role in certain environmentally caused diseases, including some types of cancer. Currently, different cell types, especially alveolar type II cells and nonciliated bronchiolar epithelial cells (Clara cells), are being isolated from rat lungs so that a detailed examination of the toxication-detoxication processes in purified cell types and in individual cells may be carried out. Different lung cell types have different intrinsic abilities to metabolize various chemical compounds, including benzo(a)pyrene, and these activities are inducible to different extents. Also, treatment of animals with monooxygenase inducers alters the balance of toxication-detoxication enzyme systems in the different lung cell types.